全文获取类型
收费全文 | 605篇 |
免费 | 71篇 |
出版年
2023年 | 4篇 |
2021年 | 12篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 13篇 |
2017年 | 8篇 |
2016年 | 16篇 |
2015年 | 20篇 |
2014年 | 28篇 |
2013年 | 40篇 |
2012年 | 32篇 |
2011年 | 35篇 |
2010年 | 26篇 |
2009年 | 21篇 |
2008年 | 26篇 |
2007年 | 28篇 |
2006年 | 26篇 |
2005年 | 16篇 |
2004年 | 21篇 |
2003年 | 32篇 |
2002年 | 21篇 |
2001年 | 14篇 |
2000年 | 20篇 |
1999年 | 19篇 |
1998年 | 10篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 13篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1968年 | 3篇 |
1945年 | 3篇 |
1942年 | 6篇 |
排序方式: 共有676条查询结果,搜索用时 281 毫秒
601.
Accounting for uncertainty in marine reserve design 总被引:2,自引:0,他引:2
Ecosystems and the species and communities within them are highly complex systems that defy predictions with any degree of certainty. Managing and conserving these systems in the face of uncertainty remains a daunting challenge, particularly with respect to developing networks of marine reserves. Here we review several modelling frameworks that explicitly acknowledge and incorporate uncertainty, and then use these methods to evaluate reserve spacing rules given increasing levels of uncertainty about larval dispersal distances. Our approach finds similar spacing rules as have been proposed elsewhere – roughly 20–200 km – but highlights several advantages provided by uncertainty modelling over more traditional approaches to developing these estimates. In particular, we argue that uncertainty modelling can allow for (1) an evaluation of the risk associated with any decision based on the assumed uncertainty; (2) a method for quantifying the costs and benefits of reducing uncertainty; and (3) a useful tool for communicating to stakeholders the challenges in managing highly uncertain systems. We also argue that incorporating rather than avoiding uncertainty will increase the chances of successfully achieving conservation and management goals. 相似文献
602.
603.
Bioinformatic and comparative localization of Rab proteins reveals functional insights into the uncharacterized GTPases Ypt10p and Ypt11p
下载免费PDF全文
![点击此处可从《Molecular and cellular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Buvelot Frei S Rahl PB Nussbaum M Briggs BJ Calero M Janeczko S Regan AD Chen CZ Barral Y Whittaker GR Collins RN 《Molecular and cellular biology》2006,26(19):7299-7317
A striking characteristic of a Rab protein is its steady-state localization to the cytosolic surface of a particular subcellular membrane. In this study, we have undertaken a combined bioinformatic and experimental approach to examine the evolutionary conservation of Rab protein localization. A comprehensive primary sequence classification shows that 10 out of the 11 Rab proteins identified in the yeast (Saccharomyces cerevisiae) genome can be grouped within a major subclass, each comprising multiple Rab orthologs from diverse species. We compared the locations of individual yeast Rab proteins with their localizations following ectopic expression in mammalian cells. Our results suggest that green fluorescent protein-tagged Rab proteins maintain localizations across large evolutionary distances and that the major known player in the Rab localization pathway, mammalian Rab-GDI, is able to function in yeast. These findings enable us to provide insight into novel gene functions and classify the uncharacterized Rab proteins Ypt10p (YBR264C) as being involved in endocytic function and Ypt11p (YNL304W) as being localized to the endoplasmic reticulum, where we demonstrate it is required for organelle inheritance. 相似文献
604.
Low birth weight is associated with both later adult diseases such as type 2 diabetes mellitus and a number of metabolic abnormalities, the foremost of which is insulin resistance. Indeed the link between an adverse perinatal environment, manifested by low birth weight, and adult life pathology may be an early, permanent reduction in insulin sensitivity. A reduction in insulin sensitivity has been demonstrated in small for gestational age (SGA), term subjects from childhood through to adulthood. Less is known about children born premature into an adverse neonatal environment. We present data demonstrating that premature infants also have metabolic abnormalities similar to those observed in term, SGA children and that these occur irrespective of whether they are SGA or appropriate for gestational age (AGA). 相似文献
605.
Nanda KK Nolt MB Cato MJ Kane SA Kiss L Spencer RH Wang J Lynch JJ Regan CP Stump GL Li B White R Yeh S Bogusky MJ Bilodeau MT Dinsmore CJ Lindsley CW Hartman GD Wolkenberg SE Trotter BW 《Bioorganic & medicinal chemistry letters》2006,16(22):5897-5901
This letter describes the discovery of a novel series of potent Kv1.5 ion channel antagonists based on a diisopropyl amide scaffold. Structure-activity relationships of functionalized analogs are discussed. Key compound 1-(3-(diisopropylcarbamoyl)-2-phenyl-3-(pyridin-3-yl)propyl)-3-(2-fluorobenzyl)urea (10) exhibits significant atrial-selective effects in an in vivo model. 相似文献
606.
Cox KM Sterling JD Regan JT Gasdaska JR Frantz KK Peele CG Black A Passmore D Moldovan-Loomis C Srinivasan M Cuison S Cardarelli PM Dickey LF 《Nature biotechnology》2006,24(12):1591-1597
N-glycosylation is critical to the function of monoclonal antibodies (mAbs) and distinguishes various systems used for their production. We expressed human mAbs in the small aquatic plant Lemna minor, which offers several advantages for manufacturing therapeutic proteins free of zoonotic pathogens. Glycosylation of a mAb against human CD30 was optimized by co-expressing the heavy and light chains of the mAb with an RNA interference construct targeting expression of the endogenous alpha-1,3-fucosyltransferase and beta-1,2-xylosyltransferase genes. The resultant mAbs contained a single major N-glycan species without detectable plant-specific N-glycans and had better antibody-dependent cell-mediated cytotoxicity and effector cell receptor binding activities than mAbs expressed in cultured Chinese hamster ovary (CHO) cells. 相似文献
607.
Douglas C. Beshore Nigel J. Liverton Charles J. McIntyre Christopher F. Claiborne Brian Libby J. Christopher Culberson Joseph J. Salata Christopher P. Regan Joseph J. Lynch Laszlo Kiss Robert H. Spencer Stephanie A. Kane Rebecca B. White Suzie Yeh George D. Hartman Christopher J. Dinsmore 《Bioorganic & medicinal chemistry letters》2010,20(8):2493-2496
A series of triarylethanolamine inhibitors of the Kv1.5 potassium channel have been prepared and evaluated for their effects in vitro and in vivo. The structure–activity relationship (SAR) studies described herein led to the development of potent, selective and orally active inhibitors of Kv1.5. 相似文献
608.
Declining home range area predicts reduced late‐life survival in two wild ungulate populations
下载免费PDF全文
![点击此处可从《Ecology letters》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hannah Froy Luca Börger Charlotte E. Regan Alison Morris Sean Morris Jill G. Pilkington Michael J. Crawley Tim H. Clutton‐Brock Josephine M. Pemberton Daniel H. Nussey 《Ecology letters》2018,21(7):1001-1009
Demographic senescence is increasingly recognised as an important force shaping the dynamics of wild vertebrate populations. However, our understanding of the processes that underpin these declines in survival and fertility in old age remains limited. Evidence for age‐related changes in foraging behaviour and habitat use is emerging from wild vertebrate studies, but the extent to which these are driven by within‐individual changes, and the consequences for fitness, remain unclear. Using longitudinal census observations collected over four decades from two long‐term individual‐based studies of unmanaged ungulates, we demonstrate consistent within‐individual declines in home range area with age in adult females. In both systems, we found that within‐individual decreases in home range area were associated with increased risk of mortality the following year. Our results provide the first evidence from the wild that age‐related changes in space use are predictive of adult mortality. 相似文献
609.
Electricity-producing bacterial communities in microbial fuel cells 总被引:29,自引:0,他引:29
Microbial fuel cells (MFCs) are not yet commercialized but they show great promise as a method of water treatment and as power sources for environmental sensors. The power produced by these systems is currently limited, primarily by high internal (ohmic) resistance. However, improvements in the system architecture will soon result in power generation that is dependent on the capabilities of the microorganisms. The bacterial communities that develop in these systems show great diversity, ranging from primarily delta-Proteobacteria that predominate in sediment MFCs to communities composed of alpha-, beta-, gamma- or delta-Proteobacteria, Firmicutes and uncharacterized clones in other types of MFCs. Much remains to be discovered about the physiology of these bacteria capable of exocellular electron transfer, collectively defined as a community of "exoelectrogens". Here, we review the microbial communities found in MFCs and the prospects for this emerging bioenergy technology. 相似文献
610.